The invention relates to a targeting apparatus for a locking nail.
The targeting apparatus of the present invention is particularly suited for supracondylar nails. Such a nail is shown in U.S. Pat. No. 6,010,505, the teachings of which are incorporated herein by reference. As is known, supracondylar nails are driven into the bony canal via the end of the distal femur. They serve for taking care of fractures in the condylar range of the femur. A nail of this type is designed as a locking nail, i.e. it is provided with cross-bores through which locking screws are passed to securely anchor the nail in the femur. A targeting apparatus is required to locate the cross-bores of a locking nail.
One type of targeting apparatus for locking nails is the one where the targeting apparatus is placed onto one end of the locking nail. Here, the targeting apparatus also serves as a hammering instrument to drive the nail into the femoral canal. On its target arm, the target apparatus has at least one target bore which is aligned with a bore in the nail shank. After the nail is knocked or hammered in, a hole is drilled into the bone via the target bore before the locking screws are threaded in. Such a targeting device is shown in U.S. Pat. No. 6,039,739.
It is known for locking nails to have the cross-bores arranged at different angles and distances. It is further known to offset to axes of the cross-bores by predetermined angles in the circumferential direction of the nail. Furthermore, it is known to provide nails of different lengths with their cross-bores having different distances from the distal end. Unless particular provisions are made, a separate targeting apparatus would be required for each of the different nails. This results in an unacceptably large number of targeting devices and related cost when a large number of such nails are provided.